Aircraft Transmission Lubrication Assembly for Bubble-Stable Emergency Flow
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Solution Overview
Problem
Existing transmission assemblies for hovering aircraft face instability in lubrication oil flow during emergency conditions, particularly due to air bubbles obstructing nozzles and non-adjustable pressure drop, leading to insufficient lubrication of critical components like bearings.
Innovation Solution
The transmission assembly incorporates a dosing device with concentrated pressure drop sections and a passive emergency lubrication circuit, where the dosing device slows down lubricating oil flow through multiple orifices, allowing air bubbles to rise and preventing clogging, while the emergency circuit is designed to facilitate continuous lubrication by gravity-fed oil flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the passage section of the emergency circuit nozzle is made smaller to extend emergency lubrication time, then the emergency lubrication duration is improved, but air bubbles easily obstruct the nozzle outlet causing flow instability
Solution Approach 1:
The emergency circuit is segmented into two functional parts: a dosing device with multiple orifices for bubble separation and a nozzle for lubrication delivery. This segmentation allows the system to extend emergency lubrication time through the dosing device's bubble separation capability while maintaining flow stability through the dedicated nozzle design.
Solution Approach 2:
The dosing device acts as an intermediary component between the emergency tank and the nozzle. It mediates the oil flow by separating air bubbles from the lubricating oil before the oil reaches the nozzle, thus preventing bubble obstruction while extending the emergency lubrication duration.
2Duration of action of moving object
If a distributed pressure drop is used in the emergency circuit nozzle, then the lubrication flow is extended, but the emptying time becomes non-adjustable once the nozzle length is defined
Solution Approach 1:
The system uses multiple orifices with variable dimensions (different diameters and configurations) to change the pressure drop parameters. By selecting different orifice sizes and arrangements in the dosing device, the emptying time can be adjusted while maintaining stable lubrication flow duration.
3Reliability
If concentrated pressure drop sections are introduced through multiple orifices, then air bubbles can rise and clogging is prevented, but the device complexity increases
Solution Approach 1:
The dosing device is segmented into multiple discrete orifices arranged in a compact configuration. This segmentation creates multiple concentrated pressure drop sections that enable bubble separation while maintaining a relatively simple overall structure that does not significantly increase device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the stability and reliability of lubrication during emergency conditions, ensuring consistent lubrication of bearings and extending the emergency lubrication time by preventing air bubble-induced clogging and adjusting the emptying time of the emergency tank.
Implementation Method 1
said passage 33 defines a plurality of concentrated pressure drop sections 6 for the lubricating oil
Implementation Method 2
The passage 33 defines a plurality of concentrated pressure drop sections 6 for the lubricating oil which slow down a flow of lubricating oil coming from the conduit 32, so as to allow air bubbles, which are enclosed in the lubricating oil, to rise
Implementation Method 3
designed to facilitate continuous lubrication by gravity-fed oil flow
Data Source
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AI summary
Transmission assembly (3, 3', 3", 3‴, 3"") for an aircraft (1) capable of hovering, comprising: a first and a second member (7, 8) and support means (9) of the first member (7) with respect to the second member (8); a primary lubrication circuit (20) comprising a primary tank (11) of a lubricating fluid and primary fluidic supply means (12) for supplying fluid to the support means (9); and an emergency lubrication circuit (22) comprising an emergency tank (23) of lubricating fluid fluidically connected to the primary tank (11); and auxiliary fluidic supply means (30) of the lubricating fluid to the support means (9), comprising a nozzle (24); the auxiliary fluidic supply means (30) comprise a dosing device (31, 31', 31", 31‴, 31"") and a fluidic line (32), which fluidically connects the emergency tank (23) with the dosing device (31, 31', 31", 31‴, 31""); the dosing device (31, 31', 31", 31‴, 31"") comprising a passage (33, 33"") for the lubricating fluid from the fluidic line (32) to the nozzle (24), which comprises a plurality of concentrated pressure drop sections (6, 6""), which are distinct and spaced apart from each other.